vfs.file

data type

Library: File system utilities (OMVFS)
Import : omvfs.xmd

Purpose

The VFS file opaque data type represents an individual file.

Usage Notes

The OmniMark Virtual File System dynamic link library file ("omvfs.dll") creates the VFS file data type. The related module file ("omvfs.xmd") defines the interface to that data type. To use VFS file data types in your program, you must import it into your program using a statement like this:

  import "omvfs.xmd" prefixed by vfs.

(Please see the import topic for more on importing.)

Please refer to Opaque Data Types for a general description of opaque data types and how they are used.

Related OMVFS library functions:

The functions

vfs.open - open a file.
vfs.close - close a file.

are used to open and close files. VFS file objects are used by the following OMVFS library functions:

vfs.cursor-position - get the current position of the cursor in a VFS file object.
vfs.describe-file - return a set of attributes describing a file.
vfs.file-directory - get the directory location of the file.
vfs.file-name - get the file name of a VFS file object.
vfs.lock - lock an entire VFS file object or a specific area of it.
vfs.move-cursor - change the cursor position from the current location in a file's contents to the position you specify.
vfs.reader - read the contents of a VFS file and return them in an OmniMark source.
vfs.truncate - truncate a file at a specified byte.
vfs.unlock - unlock a single locked section or an entire file.
vfs.writer - obtain an output object (write) to an open file.

Example: Opening a file

  import "omvfs.xmd" prefixed by vfs.
  process
    local vfs.file myFile
    local vfs.directory myDir
    local stream attributes-shelf variable
    set myDir to vfs.connect "file:///omprogs/"
    set myFile to vfs.open "jean-sibelius.txt" on myDir for vfs.read-mode 
    vfs.describe-file myFile into attributes-shelf
    output "    Name:   " || attributes-shelf{"name"} || "%n"
    output "    Size:   " || attributes-shelf{"size"} || " bytes%n"
    do when attributes-shelf{"isdir"} = 0
      output "    Type:   file" || "%n"
    else
      output "    Type:   directory" || "%n"
    done
    output "Contents:  " || vfs.reader on myFile || "%n"

This program produces the following output:

  Name:   file:///omprogs/jean-sibelius.txt
      Size:   115 bytes
      Type:   file
  Contents:  "Pay no attention to what the critics say; no statue has ever been erected to a critic."
       -- Jean Sibelius